Density Functional Simulation of a Breaking Nanowire

Nakamura, Atsunobu; Brandbyge, Mads; Hansen, Lars Henrik; Jacobsen, Karsten Wedel

doi:10.1103/physrevlett.82.1538

Cited by 96 publications

(90 citation statements)

References 23 publications

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“…The shapes of the curves reveal the existence of a strong correlation between conductance and the nanocontact neck section size, in agreement with previous numerical results for other materials. 4,19,24 A striking fact is that for values S m Ϸ 1 ͑defining a nanocontact of one-atom section͒ there are two different conductance values ͑G / G 0 Ϸ 2 and Ϸ1͒. We have confirmed that this fact is explained in terms of the presence of two different atomic arrangements 7 at the last stage of the breaking process.…”

supporting

confidence: 72%

Ballistic resistivity in aluminum nanocontacts

et al. 2005

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We perform a representative series of semiclassical molecular dynamics simulations of aluminum nanocontact breakages, coupled to full quantum conductance calculations. This approach allows to obtain realistic conductance histograms of polyvalent species and understand the origin of their peaked structures. The results show that the conductance depends linearly on the contact minimum cross section for the geometrically favored nanocontact configurations. Valid in a broad range of conductance values, such relation suggests the definition of a transport parameter for the nanoscale, that represents the novel concept of ballistic resistivity. One of the major industrial challenges is to profit from some fascinating physical features present at the nanoscale. The production of dissipationless nanoswitches ͑or nanocontacts͒ is one of such attractive applications. 1 The inelastic electron mean free path is usually larger than nanocontact typical cross sections ͑of the order of few atoms in controlled experimets͒ even at room temperature, and, therefore, the electronic transport through these nanoconstrictions is expected to be ballistic. Nevertheless, the lack of knowledge of the real efficiency of this electronic ballistic/nondissipative transport limits future innovations.For contact sizes of the order of a few Fermi wavelengths F , well defined modes ͑channels͒ appear associated with the transversal confinement of electrons. For this situation, the conductance G is given by the Landauer formula G = G 0 ͚ n=1 N T n , where G 0 =2e 2 / h is the conductance quantum ͑e being the electron charge and h Planck's constant͒, T n is the transmission probability of the nth channel, and N is the number of propagating modes with energies below the Fermi energy. 2 It has been shown that the number of conducting channels is determined by the number of valence electrons of the respective chemical element. 3 For monovalent noble metals such as Cu, Ag and Au, the transmission probability T has been estimated to be approximately equal to 1 ͑i.e., each noble-metal atom contact contributes with G 0 to the conductance value 4,5 ͒. But for monovalent alkali metals or polyvalent chemical species, single-atom contact studies revealed that this channel transmittivity can have a result smaller than one. 3,6,7 Nowadays, there exist several experimental techniques to characterize the electronic transport through nanocontacts. Among them, the measurement of the conductance histogram during nanocontact breakages 8-10 is one of the most used. By putting in contact two opposite electrodes and then separating them, one observes a stepwise decrease in the electrical conductance ͑i.e., a conductance scan͒, until the breakpoint is reached. [11][12][13][14] It has been shown that each scan of the conductance dependence on the electrode retraction differs from one another, since the nanocontact structural evolutions during breakages are not identical. 15 Notwithstanding for fixed experimental parameter conditions ͑such as temperature and applied voltage...

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supporting

confidence: 72%

Ballistic resistivity in aluminum nanocontacts

et al. 2005

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“…Similar atomicscale metallic nanowires have been produced from Au by a scanning tunneling microscope 2,3 and by the mechanically controllable break junction technique. 4 The formation of Na nanowires has been investigated by first-principles calculations [5][6][7] and the ensuing conductances have been compared with experiments. 7 The conductance of a nanowire shows nonmonotonic behavior as a function of its length.…”

Section: Introductionmentioning

confidence: 99%

“…4 The formation of Na nanowires has been investigated by first-principles calculations [5][6][7] and the ensuing conductances have been compared with experiments. 7 The conductance of a nanowire shows nonmonotonic behavior as a function of its length. However, the role of the contact leads cannot be ignored, as shown by Sim et al 8 and Yeyati et al 9 The purpose of this paper is to study the dependence of the conductance not only on the length but also on the shape of the contacts.…”

Section: Introductionmentioning

confidence: 99%

Conductance oscillations in metallic nanocontacts

et al. 2002

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We examine the conductance properties of a chain of Na atoms between two metallic leads in the limit of low bias. Resonant states corresponding to the conductance channel and the local charge neutrality condition cause conductance oscillations as a function of the number of atoms in the chain. Moreover, the geometrical shape of the contact leads influences the conductivity by giving rise to additional oscillations as a function of the lead opening angle.

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“…In recent years, the deformation of nanowires have been studied by molecular dynamics simulations using either embodied-atom-method (EAM) [12][13][14][15] or effective-medium theory (EMT) [16,17] potentials as well as first-principles method based on the density functional theory (DFT) [18][19][20][21]. These studies focus on the correlation of the force (associated with the changes in the bonding of the nanowire) and the conductance for the metallic Au, Ni, and Na nano-contacts [17,22] and Au, Ni, Al, Na, and SiSe 2 nanowire [12,16,20,23]. The structural transformation takes place in nanoscale metallic wires under uniaxial strain [12,14,[17][18]23].…”

Section: Introductionmentioning

confidence: 99%

The uniaxial tensile deformation of Ni nanowire: atomic-scale computer simulations

Zhu

Shao

et al. 2005

Physica E: Low-dimensional Systems and Nanostructures

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The mechanical deformations of nickel nanowire subjected to uniaxial tensile strain at 300 K are simulated by using molecular dynamics with the quantum corrected Sutten-Chen many-body force field. We have used common neighbor analysis method to investigate the structural evolution of Ni nanowire during the elongation process. For the strain rate of 0.1%/ps, the elastic limit is up to about 11% strain with the yield stress of 8.6 GPa. At the elastic stage, the deformation is carried mainly through the uniform elongation of the distances between the layers (perpendicular to the Z-axis) while the atomic structure remains basically unchanged. With further strain, the slips in the {1 1 1} planes start to take place in order to accommodate the applied strain to carry the deformation partially, and subsequently the neck forms. The atomic rearrangements in the neck region result in a zigzag change in the stress-strain curve; the atomic structures beyond the region, however, have no significant changes. With the strain close to the point of the breaking, we observe the formation of a one-atom thick necklace in Ni nanowire. The strain rates have no significant effect on the deformation mechanism, but have some influence on the yield stress, the elastic limit, and the fracture strain of the nanowire. r

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Density Functional Simulation of a Breaking Nanowire

Cited by 96 publications

References 23 publications

Ballistic resistivity in aluminum nanocontacts

Ballistic resistivity in aluminum nanocontacts

Conductance oscillations in metallic nanocontacts

The uniaxial tensile deformation of Ni nanowire: atomic-scale computer simulations

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